body{
    background: url("https://www.cdnjson.com/images/2021/08/10/path-of-light-2027220_1920.jpg") no-repeat;
    background-size: auto;
    font-family: Arial, serif;
    height: 100%;
    padding: 10px 20%;
}
*{
    box-sizing: border-box;
    padding: 0;
    margin: 0;
}
.header h1{
    font-size: 50px;
    font-weight: bolder;
}
.header{
    padding: 18px;
    text-align: center;
}
.NavigationBar{
    overflow: hidden;
    background-color: #333;
    position: sticky;
    top: 0;
    box-shadow: 0 1px 1px 0 rgb(0 0 0.2), 0 1px 1px 0 rgb(0 0 0.2);
    text-align: center;
}
.NavigationBar li {
    padding-left: 10px;
    padding-right: 10px;
    display: inline-block;
}
.NavigationBar ul{
    list-style-type: none;
    overflow: hidden;
}
.NavigationBar a{
    float: left;
    display: block;
    font-size: 20px;
    font-weight: bolder;
    color: #f2f2f2;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;/*去除链接的下划线*/
}
.footer {
    padding: 10px;
    text-align: center;
    color: #333;
    margin-top: 30px;
}

.body{
    min-height: 330px;
    background-color: white;
    margin-top: 20px;
    box-shadow: 0 4px 4px 0 rgb(0 0 0.2), 0 4px 4px 0 rgb(0 0 0.2);
    animation: bodyLoad 2s;
}
.body h3{
    padding: 10px;
    background-color: #333;
    text-align: center;
    color: white;
}
/*页面淡入动画效果*/
@keyframes bodyLoad {
    from {
        opacity: 0;
        transform: translate3d(0, 20%, 0);
    }
    to {
        opacity: 1;
        transform: none;
    }
}

